Railway systems of the type presently gaining favor in large metropolitan areas in which railway cars travel in close succession typically do not have switches in which rail sections are moved, as in conventional railroads. Rather than using switches at branch intersections, the direction of traverse at the branch is established by the placement of auxiliary direction control rails and control wheels on the vehicle which follow the auxiliary direction control rails. Rail systems of this type, including monorail systems, utilize two sets of wheels including traction support wheels rotating on horizontal axes and a separate set of guide wheels disposed on vertical axes. With this type of installation, the surfaces upon which the wheels travel are part of the support system and are called "girder road systems" having either bottom-supported or suspended railway vehicles. The supporting girders must have large dimensions in order to guarantee the required rigidity as well as the safe guidance of the vehicles. One such prior art development is disclosed in German Patent Publication DT-OS 2,034,106. However, with this system, wheels with flanges are utilized to guide the vehicles along the main course with laterally displaceable auxiliary wheels to guide the vehicles when traversing a branch intersection. However, because of the need for rigid impact surfaces in order to utilize the flanges, such arrangements are not entirely satisfactory for use in cities due to the resulting noise.
A further monorail system development is disclosed in U.S. Pat. No. 3,799,062 which teaches a double U-shaped girder or monorail for the vehicles equipped with support wheels without flanges. Moreover, that patent teaches the use of guide wheels and separate direction control wheels engaging vertical surfaces. However, with this particular arrangement the opposed guide surfaces are spaced so far apart from each other that there is difficulty in aligning the two opposed guiding surfaces, particularly in those areas where the guiding surfaces are curved adjacent a branch intersection. If the two spaced opposed guiding surfaces are not completely and accurately aligned, there is the possibility that the wheels will become jammed at such intersections or at least that they will be subject to a high degree of wear. Thus, it has been found desirable to utilize a single guide surface on one side of the vehicle path in branch connection or intersection areas so as to eliminate the need for the precise alignment of opposed guiding surfaces in those areas. This, in turn, eliminates opposed forces generated by the use of two such opposed guiding surfaces in the branch intersection areas.
With this invention, a rail installation of the girder road or monorail type is provided which utilizes single auxiliary branch guide surfaces or conductor rails on one side of the vehicle path in the branch intersection areas, so that the vehicles are guided precisely and eliminates the cost involved in having to precisely align opposed guiding surfaces on each side of the vehicle path in those areas. This is achieved by providing the regular guide surfaces on the side of the vehicle opposite to the auxiliary branch guide surface being utilized at any one branch intersection with a recessed area so that the opposed regular guide wheels in those areas where the direction control wheels are guiding the vehicle, do not come in contact with any guide surface on the opposite side of the vehicle. Thus, no opposing forces are generated on either side of the vehicle to cause jamming between the opposed regular guide wheels or unnecessary wear of the impact surfaces thereof.
The conductor or auxiliary branch guide rails are tapered at the entry and exit ends thereof. Thus, at the moment the guide wheels come in contact with the tapered entry end of the auxiliary branch guide rail they are put into a rotary motion. Also at this moment, the direction control wheels, arranged at the same side of the vehicle, reach the auxiliary branch guide rail surface tapered inward as well so that the vehicle is only guided on one side of the vehicle through the interaction between the direction control wheel and the single auxiliary guide rail on that side of the vehicle. Because of the recessed area on the opposite side of the vehicle along the regular guide surface, the guide wheels and the direction control wheels on that opposite side of the vehicle are not in touch with any surface. This eliminates any opposed or double guidance which might generate opposed forces causing jamming of the wheels between two such opposed guiding surfaces. The regular guide surface gradually recedes or tapers into its recessed area the exact amount of the taper of the auxiliary branch guide rails on the opposite side of the vehicle course.
A further feature of the invention is that a lightweight material such as aluminum or a resin is used for the wheel body of the regular guide wheels and the direction control wheels of the invention here. this is particularly helpful because the guide wheels reverse rotation from the regular guide surface to the auxiliary direction control surface and the reduced weight reduces the degree of inertia involved in the changing of direction of rotation. This reduces jolts or a feeling of impact on the vehicle itself during this change of direction. Moreover, preferably, in accordance herewith, the direction control wheels are of a lesser diameter than the associated guide wheels therewith. Thus, when the vehicle is travelling along a regular course of the system when the direction control wheels are swung into the path of their associated guide wheels, the direction control wheels do not touch the guide surfaces. Also, in order to compensate for track clearance and manufacturing tolerances, the distance between the recessed area of the regular guide surface and the opposed auxiliary branch guide rail surface at the initial area of branch intersection is within the range of between about two and ten millimeters greater than the diameter of the guide wheels. Preferably, the support wheels, as well as the guide wheels will have resilient bearing surfaces in order to reduce noise and absorb impacts between the wheel surfaces and the guide surfaces therefor.
Also in accordance with this invention, and as discussed in more detail below, the direction control wheels pivot around the vertical axis of their associated guide wheels so that they are located in the guide wheel path when not in use, as discussed above, and when they are in use they pivot laterally to a position adjacent the guide wheel path. The distance between the guide wheels and their associated direction control wheels equals the distance between the opposed guiding surfaces of each individual branch conductor or auxiliary guide rail.
For the safe guidance of the vehicles, in accordance herewith, the direction control wheels are arranged adjacent the four corners of the vehicles involved in the installation and all are connected by a linkage which provides simultaneous shifting, which linkage is equipped with a jamming guard which shifts the direction control wheel immediately before the vehicle enters a branch intersection so as to direct the proper traverse of the vehicle through the intersection. The jamming guard may be in the form of a cam which engages a cam guiding surface for the proper switch direction of the vehicle for its traverse. For further details concerning this linkage arrangement and its method of operation, reference is made to the teachings of U.S. Pat. No. 3,828,691, which is hereby incorporated by reference.
For a more complete understanding of the present invention and a better appreciation of its intended advantages, reference should be made to the following description of one embodiment of the new and improved railway apparatus taken in conjunction with the accompanying drawings illustrating the invention.